Air pollution includes emissions from two sources: fixed sources and moving sources. A fixed source could be an electric power generation facility or a lime kiln. A moving source can be a tail pipe such as one on an automobile. The fixed source's emissions are redirected downward into a depleted hydrocarbon reserve through an injection well. The moving source is attached to a Carbonator which takes calcium oxide from the lime kiln and carbon dioxide from the moving source to produce calcium carbonate. This removes two sources of air pollution, first the use of the Carbonator system to remove Carbon Dioxide Emissions into the Atmosphere as described in the Application and secondly the total injection of all smokestack effluents into depleted reservoirs, removing the smokestack and in an electrical generating station HVDC transmission lines are run to the displaced smokestack, and is thus a solution to air pollution.

The present invention aims to provide techniques for efficiently preparing calcium carbonate particles having an average primary particle size of less than 1 m. Calcium carbonate microparticles having an average primary particle size of less than 1 m can be synthesized efficiently by synthesizing calcium carbonate in the presence of cavitation bubbles.

A method for preparing nano silica and nano calcium carbonate using rice hull ash and flue gas. The method includes: 1) adding rice hull ash to a sodium hydroxide solution, to yield a first mixed solution; stirring and heating the first mixed solution; then filtering the first mixed solution to yield a first filtrate; 2) adding the first filtrate to a reaction still, and diluting the first filtrate; adding polyethylene glycol as a dispersant to the reaction solution; introducing flue gas to the reaction solution; filtering the reaction mixture to yield a first filter cake and a second filtrate; washing the first filter cake to a neural pH, slurrying and drying the first filter cake to yield nano silica; and 3) mixing the second filtrate and a washing solution collected from 2); adding a calcium hydroxide solution to the reaction still, to yield nano calcium carbonate.

Provided herein are methods and systems to form calcium carbonate comprising vaterite, comprising dissolving lime in an aqueous base solution under one or more precipitation conditions to produce a precipitation material comprising calcium carbonate and a supernatant solution, wherein the calcium carbonate comprises vaterite.

The present invention is directed to the use of a mineral material as anti-pollution cosmetic agent, wherein the mineral material has a volume median particle size d.sub.50(vol) from 0.1 to 90 ?m, a volume top cut particle size d.sub.98(vol) of below 250 ?m, and is selected from surface-reacted calcium carbonate, hydromagnesite, or mixtures thereof. Furthermore, the present invention relates to an anti-pollution cosmetic composition comprising said mineral material as well as a cosmetic method of protecting a keratin material from pollutants comprising the application of said anti-pollution cosmetic composition onto the keratin material.

A process for converting gypsum into precipitated calcium carbonate including reacting a mixture comprising gypsum and a seed, a mineral acid, or both with at least one carbonate source, whereby precipitated calcium carbonate is produced in the form of calcite and/or aragonite directly without conversion from a vaterite polymorph. Also, a process for converting gypsum into precipitated calcium carbonate including providing a mixture comprising i) gypsum ii) a seed, a mineral acid, or both iii) at least one additive selected from the group consisting of ammonium sulfate, an organic acid, or an iron material, and reacting the mixture with at least one carbonate source to produce precipitated calcium carbonate in the form of vaterite. The precipitated calcium carbonates having desired and unique compositions, polymorph and crystal size characteristics formed by these processes.

A process for converting gypsum into precipitated calcium carbonate including reacting a mixture comprising gypsum and a seed, a mineral acid, or both with at least one carbonate source, whereby precipitated calcium carbonate is produced in the form of calcite and/or aragonite directly without conversion from a vaterite polymorph. Also, a process for converting gypsum into precipitated calcium carbonate including providing a mixture comprising i) gypsum ii) a seed, a mineral acid, or both iii) at least one additive selected from the group consisting of ammonium sulfate, an organic acid, or an iron material, and reacting the mixture with at least one carbonate source to produce precipitated calcium carbonate in the form of vaterite. The precipitated calcium carbonates having desired and unique composition, polymorph and crystal size characteristics formed by these processes.

The present invention relates to precipitated calcium carbonate particles being at least partially in the form of nanofibers or nanochain like agglomerates, wherein the particles are at least partially coated with at least one coating agent, use of such precipitated calcium carbonate particles and a process for the manufacture of such precipitated calcium carbonate particles.

A method for obtaining particulate calcium carbonate exhibiting improved brightness and color and having uniformity of size such that when the particles are formed in the causticization process in a kraft pulp mill, the time required to separate the particles from liquors in which they are suspended is minimized and the amount of liquor recovered is maximized, with minimal dilution by water used for washing. The method includes the steps of a) slaking calcium oxide in water or an alkaline liquor containing as dissolved species predominantly sodium hydroxide; b) mixing the slaked lime with green liquor from a kraft pulping process to complete a causticization reaction that produces white liquor and lime mud; c) separating the lime mud from the white liquor; and d) milling a portion of the lime mud for use as a white mineral pigment in applications where such pigments are typically used.

The present invention is directed to a process for producing precipitated calcium carbonate with improved resistance to structural breakdown, wherein the milk of lime is carbonated in the presence of at least one gas other than carbon dioxide, or the carbonation is carried out in the presence of a static gas bubble comminution unit as well as to precipitated calcium carbonate obtained by such a process.